Fuel nozzle having improved mixing tube element and turbomachine having fuel nozzle

Abstract

To provide a turbomachine, a combustor and a fuel nozzle capable of sending alternative fuel (hydrogen, etc.) and air for combustion without causing flame holding or flash back.SOLUTION: A fuel nozzle (22) for a combustor of a turbomachine includes a housing (210) and a plurality of mixing tube elements (230) surrounded by the housing (210). At least one of the plurality of mixing tube elements (230) includes a body extending between a first end and a second end and defines a passage extending through the body between the first end and the second end. The first end is closed, and the second end is open. The body further defines a first fluid inlet and a second fluid inlet. The first fluid inlet is defined between the first end and the second end, and the second fluid inlet is defined between the first fluid inlet and the second end.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates generally to fuel nozzles, and more particularly to turbomachines with improved mixing tube elements and fuel nozzles for turbomachine combustors. More particularly, the present invention relates to the claimed technology. [Background technology]

[0002] Turbomachines are utilized in various industries and applications for energy transfer. For example, a gas turbine engine is a turbomachine that typically includes a compressor section, a combustion section, a turbine section, and an exhaust section. The compressor section gradually increases the pressure of a working fluid entering the gas turbine engine and supplies the compressed working fluid to the combustion section. The compressed working fluid and fuel (e.g., natural gas) are mixed in the combustion section and combusted in a combustion chamber to generate high-pressure, high-temperature combustion gases. The combustion gases flow from the combustion section to the turbine section, where they expand to produce work. For example, the expansion of the combustion gases in the turbine section rotates a rotor shaft that is connected, for example, to an electrical generator. The combustion gases then exit the gas turbine through the exhaust section.

[0003] A conventional gas turbine engine includes one or more combustors that combust a mixture of natural gas and air in a combustion chamber to produce high-pressure, high-temperature combustion gases. In some combustor sections, a primary fuel nozzle at the upstream end of the combustor injects fuel and air (the fuel / air mixture) axially into a primary combustion zone. Nitrogen oxides (NOx) and other pollutants are generated as by-products and are emitted through the exhaust section. Regulatory requirements for low emissions from gas turbines are becoming increasingly stringent, and environmental agencies worldwide are demanding further reductions in emission rates of NOx and other pollutants from both new and existing gas turbines.

[0004] Burning a mixture of natural gas and large amounts of hydrogen and / or pure hydrogen in place of natural gas in a combustor significantly reduces or eliminates NOx and other pollutant emissions. However, because the combustion characteristics of hydrogen are different from those of natural gas, conventional combustion systems cannot safely burn concentrated hydrogen and / or pure hydrogen. For example, burning concentrated hydrogen and / or pure hydrogen in conventional combustion systems can promote flashback or flame-holding conditions, in which the combustion flame moves toward the fuel delivered by the injector, which can severely damage the injector in a relatively short period of time.

[0005] Thus, there is a need in the art for turbomachines, combustors and fuel nozzles that can channel alternative fuels (such as hydrogen) and air for combustion without flame holding or flashback problems. Summary of the Invention

[0006] The present invention relates to the technology set forth in the claims. Aspects and advantages of the turbomachinery, combustor, and fuel nozzle according to the present disclosure will be set forth in, and in part will be obvious from, the following detailed description, or may be learned by practice of the technology.

[0007] In one embodiment, a fuel nozzle for a combustor of a turbomachine is provided. The fuel nozzle includes a housing and a plurality of mixing tube elements enclosed by the housing. At least one of the plurality of mixing tube elements includes a body extending between a first end and a second end, defining a passageway therethrough between the first end and the second end, the first end being closed and the second end being open. The body further defines a first fluid inlet and a second fluid inlet, the first fluid inlet being defined between the first end and the second end, and the second fluid inlet being defined between the first fluid inlet and the second end.

[0008] In another aspect, a turbomachine is provided. The turbomachine includes a compressor section, a combustion section including a combustor, the combustor including an end cover and a fuel nozzle, and a turbine section. The fuel nozzle includes a plurality of mixing tube elements surrounded by a housing. At least one of the plurality of mixing tube elements includes a body extending between a first end and a second end, defining a passage therethrough between the first end and the second end, the first end being closed and the second end being open. The body further defines a first fluid inlet and a second fluid inlet, the first fluid inlet being defined between the first end and the second end, and the second fluid inlet being defined between the first fluid inlet and the second end.

[0009] These and other features, aspects, and advantages of the present turbomachine, combustor, and fuel nozzle will become better understood with reference to the following detailed description and claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments of the disclosed technology and, together with the description, serve to explain the principles of the technology. [Brief explanation of the drawings]

[0010] The following detailed description, taken in conjunction with the accompanying drawings, fully discloses the present turbomachine, combustor, and fuel nozzle, including the best mode of making and using the present systems and methods, to enable those skilled in the art to practice them. [Figure 1] 1 is a schematic diagram of a turbomachine according to an embodiment of the present disclosure; [Figure 2] FIG. 2 is a schematic diagram of a combustion section that may be used in the turbomachine of FIG. 1 according to an embodiment of the present disclosure. [Figure 3] 1 is a cross-sectional view of a component of a combustor including a fuel nozzle having multiple mixing tube elements according to an embodiment of the present disclosure; [Figure 4] FIG. 2 is a perspective view of a mixing tube element that may be used in a fuel nozzle according to an embodiment of the present disclosure. [Figure 5] FIG. 2 is a cross-sectional view of a mixing tube element that may be used in a fuel nozzle according to an embodiment of the present disclosure. [Figure 6] 6 is a cross-sectional view of the mixing tube element of FIG. 5 taken along line AA that may be used in a fuel nozzle according to an embodiment of the present disclosure. [Figure 7] 6 is a cross-sectional view taken along line BB of the mixing tube element of FIG. 5 that may be used in a fuel nozzle according to an embodiment of the present disclosure. [Figure 8] FIG. 1 is a schematic diagram of an additive manufacturing system according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Various embodiments of the present turbomachine, combustor, and fuel nozzle are described in detail below, one or more examples of which are illustrated in the drawings. Each example is intended to be illustrative, not limiting, of the present technology. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present technology without departing from the scope and spirit of the appended claims. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Accordingly, the present disclosure covers modifications and variations provided within the scope of the appended claims and their equivalents.

[0012] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Moreover, unless specifically stated otherwise, all embodiments described herein are to be construed as illustrative.

[0013] The detailed description of the invention uses numerical and letter designations to refer to features depicted in the drawings. In the drawings and the detailed description of the invention, like or similar designations indicate like or similar components of the invention. In this specification, the terms "first," "second," and "third" are used interchangeably to distinguish one component from another, and do not denote the location or importance of the individual components.

[0014] The term "fluid" can refer to either a gas or a liquid. The term "fluid communication" means that a fluid can make a connection between given areas.

[0015] As used herein, the terms "upstream" (or "forward") and "downstream" (or "rearward") refer to relative directions with respect to fluid flow in a fluid pathway. For example, "upstream" refers to the direction from which fluid flows, and "downstream" refers to the direction from which fluid flows. However, as used herein, the terms "upstream" and "downstream" can also refer to electrical flow. The term "radial" refers to a relative direction that is substantially perpendicular to the axial centerline of a component, the term "axial" refers to a relative direction that is substantially parallel and / or coaxial with the axial centerline of a component, and the term "circumferential" refers to a relative direction about the axial centerline of a component.

[0016] Approximate terms such as "about," "approximately," and "substantially" are not limited to the exact numerical values stated. In at least some cases, the approximation corresponds to the precision of an instrument that measures the value or the precision of a method or machine for constructing or manufacturing the part and / or system. In at least some cases, the approximation corresponds to the precision of an instrument that measures the value or the precision of a method or machine for constructing or manufacturing the part and / or system. For example, approximation can refer to an error within 1%, 2%, 4%, 5%, 10%, 15%, or 20% of a particular numerical value, a numerical range, and / or any of the upper and lower limits defining the numerical range. When used in reference to an angle or direction, such terms encompass within ±10 degrees of the stated angle or direction. For example, "approximately vertical" encompasses a direction within 10 degrees in any direction (e.g., clockwise or counterclockwise) from vertical.

[0017] Terms such as "coupled," "secured," or "attached" refer to direct coupling, fixing, or attachment, as well as indirect coupling, fixing, or attachment via one or more intermediate parts or features (including integration via additive manufacturing), unless otherwise specified herein. As used herein, the terms "comprising," "comprising," and "having" encompass non-exclusive inclusion. For example, a process, method, article, or device that includes recited features is not necessarily limited to those features and may include other features not expressly recited or inherent in such process, method, article, or device. Furthermore, unless otherwise specified, the term "or" denotes an inclusive rather than an exclusive alternative. For example, a condition A or B is true if A is true (or present) and B is false (or absent), or if A is false (or absent) and B is true (or present).

[0018] In this specification and claims, ranges of numerical limitations are combinable and / or interchangeable with each other, and such ranges specify and encompass all subranges contained therein, unless otherwise clear from the context, etc. For example, all ranges disclosed herein are inclusive of their limits, and the limits can be independently combined with each other.

[0019] 1 shows a schematic diagram of one embodiment of a turbomachine, which in the illustrated embodiment is a gas turbine engine 100. While industrial or land-based gas turbines are described and illustrated herein, the present disclosure is not limited to industrial or land-based gas turbine engines unless claimed. For example, the techniques described herein may be used with any type of turbomachine, including, but not limited to, a steam turbine, an aircraft gas turbine, or a marine gas turbine.

[0020] As shown in the figure, the gas turbine engine 100 generally includes, in flow order, an intake section 112, a compressor section 114 disposed downstream from the intake section 112, a plurality of combustors (one of which is shown in FIG. 2 ) in a combustion section 116 disposed downstream from the compressor section 114, a turbine section 118 disposed downstream from the combustion section 116, and an exhaust section 120 disposed downstream from the turbine section 118. Additionally, the gas turbine engine 100 may include one or more shafts 122 coupled between the compressor section 114 and the turbine section 118.

[0021] Compressor section 114 generally includes a plurality of rotor disks 124 (one shown) and a plurality of rotor blades 126 extending radially outward from and connected to each rotor disk 124. Each rotor disk 124 is coupled to or forms an upstream portion of a shaft 122 that extends through compressor section 114. Compressor section 114 also includes a plurality of stationary vanes (not shown) that are arranged in stages with rotor blades 126 and direct flow to rotor blades 126.

[0022] Turbine section 118 generally includes a plurality of rotor disks 128 (one shown) and a plurality of rotor blades 130 extending radially outward from and connected to each rotor disk 128. Each rotor disk 128 is coupled to or forms a downstream portion of a shaft 122 that extends through turbine section 118. Turbine section 118 also includes an outer casing 131 that circumferentially surrounds the downstream portion of shaft 122 and rotor blades 130, at least partially defining a hot gas path 132 through turbine section 118. Turbine section 118 also includes a plurality of stationary vanes (not shown) that are arranged in stages with rotor blades 130 and direct flow to rotor blades 130.

[0023] During operation, a working fluid, such as air, enters the intake section 112 and enters the compressor section 114, where the air is progressively compressed by multiple compressor stages of rotating blades and stationary vanes to provide compressed air 115 to the combustors 10 ( FIG. 2 ) in the combustor section 116. The compressed air 115 is mixed with fuel and combusted in each combustor 10 to generate combustion gases 134. The combustion gases 134 flow from the combustor section 116 through a hot gas path 132 and into the turbine section 118, where energy (kinetic and / or thermal) is transferred from the combustion gases 134 to the rotor blades 130, causing the shaft 122 to rotate. The mechanical rotational energy may then be used to drive the compressor section 114 and / or to generate electricity. After exiting the turbine section 118, the combustion gases 134 may then exit the gas turbine engine 100 via the exhaust section 120.

[0024] Figure 2 is a schematic diagram of a combustor 10 in the form of a combustion can, which may be included in the combustion system 116 of Figure 1. A plurality (e.g., 8, 10, 12, 14, 16, or more) of combustion cans 10 are arranged in an annular array about a shaft 122.

[0025] 2, the combustion can 10 includes a liner 12 that contains and channels combustion gases 134 to the turbine section 118. The liner 12 may have a cylindrical liner portion and a tapered transition portion separate from the cylindrical liner portion, as in many conventional combustion systems. Alternatively, the liner 12 may have a one-piece (or "unibody") structure in which the cylindrical and tapered portions are integrated with one another. Thus, all references to the liner 12 herein encompass both conventional combustion systems having separate liners and transition pieces, as well as combustion systems having unibody liners. Furthermore, the present disclosure may equally apply to combustion systems in which the transition piece is integrated with the first-stage nozzle of a turbine (also referred to as a "transition nozzle" or "integral outlet piece").

[0026] The liner 12 is surrounded by an outer sleeve 14, which is spaced radially outward from the liner 12 to define an annulus 32 between the liner 12 and the outer sleeve 14. The outer sleeve 14 may include a flow sleeve portion at its forward end and an impingement sleeve portion at its aft end, as in many conventional combustion systems. Alternatively, the outer sleeve 14 may have a one-piece (or "unisleeve") structure in which the flow sleeve portion and the impingement sleeve portion are axially integrated with one another. As noted above, any reference herein to the outer sleeve 14 is intended to encompass both conventional combustion systems having separate flow sleeves and impingement sleeves as well as combustion systems having a uni-sleeve outer sleeve.

[0027] The head end portion 20 of the combustion can 10 includes one or more fuel nozzles 22. The fuel nozzles 22 have a fuel inlet 24 at an upstream (or inlet) end. The fuel inlet 24 may be formed through an end cover 26 at the forward end of the combustion can 10. The downstream (or outlet) ends of the fuel nozzles 22 extend through or collectively define a combustor cap 28.

[0028] The head-end section 20 of the combustion can 10 is at least partially surrounded by a forward casing 30, which is physically and fluidly coupled to a compressor discharge case 40. The compressor discharge case 40 is fluidly coupled to a compressor outlet (not shown) and defines a compressed air plenum 42 that surrounds at least a portion of the combustion can 10. Air 36 (compressed air 115 in FIG. 1 ) flows from the compressor discharge case 40 into an annulus 32 at the aft end of the combustion can 10. Because the annulus 32 is fluidly coupled to the head-end section 20, the airflow 36 travels upstream from the aft end of the combustion can 10 to the head-end section 20, where the airflow 36 reverses direction and enters the fuel nozzle 22.

[0029] Fuel and air are introduced by fuel nozzles 22 into a primary combustion zone 50 at the forward end of the liner 12, where the fuel and air combust to produce combustion gases 46. The combustion gases 46 travel downstream toward the aft end 18 of the combustion cans 10. Additional fuel and air may be introduced by one or more fuel injection assemblies 102 (also referred to herein as "fuel injectors" or "injectors") into a secondary combustion zone 60, where the fuel and air are ignited with the combustion gases 46 to produce combustion gases 56. Fuel to the fuel injection assemblies 102 is supplied via a fuel supply line 104 having an inlet 54 at the forward end of the combustor can 10. The combustion gases 46 and the combustion gases 56 form a combined combustion gas product stream 134. A combustion system with multiple axially separated combustion zones like this is referred to as an "axial fuel staging" (AFS) system, and the downstream injectors 102 are sometimes referred to as "AFS injectors."

[0030] 3 illustrates various components of the combustor 10. As shown and described, the combustor 10 may include one or more fuel nozzles 22, each of which may extend through an end cover 26 at the forward end of the combustor 10. The downstream (or outlet) ends of the fuel nozzles 22 extend through or collectively define a combustor cap 28 (FIG. 2), 232 (FIG. 3).

[0031] 3 , fuel nozzle 22 may include a fluid supply conduit 200 extending between an inlet 202 and an outlet 204. Inlet 202 may be defined in end cover 26. A fluid passageway 206 through which a fluid flows may be defined through conduit 200 between inlet 202 and outlet 204. Inlet 202 and outlet 204 may be open such that fluid may enter fluid passageway 206 through inlet 202 and exit fluid passageway 206 through outlet 204. Fluid supply conduit 200 may further include a flange 108 connecting conduit 200 to end cover 26. In the exemplary embodiment, the fluid flowing through fluid conduit 200 is a fuel, such as natural gas and / or hydrogen.

[0032] In some embodiments, the fuel nozzle 22 may further include an outer housing 210 and a front plate 231 that define a first fluid plenum 212. The outer housing 210 may surround (e.g., completely or at least partially) at least a portion of the conduit 200 and may further surround (e.g., completely or at least partially) a plurality of mixing tube elements, described below.

[0033] The outlet 204 may terminate in a second fluid plenum 222. The second fluid plenum 222 may be defined by a housing 210 (which may be a single component surrounding the first and second fluid plenums or separate components surrounding each of the first and second plenums 212, 222), a front plate 231, and an end plate 232 (hereinafter also referred to as an aft plate 232, which may define or coincide with the cap 28 in FIG. 2 and be axially spaced from the front plate). An end plate such as the end plate 232 may also be referred to as an "aft plate" hereinafter. Additionally, a plurality of mixing tube elements 230 may be provided, with the housing 210 surrounding (e.g., completely or at least partially) the mixing tube elements 230. The mixing tube elements 230 are arranged in an annular array around the outlet 204 and, in some embodiments, a resonator (not shown).

[0034] A fluid, such as an oxidizing or cooling fluid, may enter the first fluid plenum 212 from the annulus 32 between the liner 12 and the outer sleeve 14 and may enter the mixing tube elements 230 through first fluid inlets as described herein. In an exemplary embodiment, the fluid entering the mixing tube elements 230 through the first fluid plenum 212 may be air. Such a fluid is referred to herein as a first fluid 240.

[0035] Fluid entering the second fluid plenum 222 through the fluid conduit 200 may enter the mixing tube element 230 through a second fluid inlet from the second fluid plenum 222, as described herein. Such fluid is referred to herein as a second fluid 250.

[0036] In some embodiments, the fuel nozzle 22 may further include an end plate 232. The end plate 232 may be located at a downstream end of the fuel nozzle 22 (e.g., near the downstream second ends of the mixing tube elements 230). These second ends may penetrate the end plate 232 to allow fluid to exit through the end plate 232. The downstream end of the outer housing 210 may terminate at the end plate 232.

[0037] 4-7, an exemplary embodiment of a mixing tube element 300 is shown. Note that the mixing tube element 300 may be utilized as one or more (e.g., all in some embodiments) of the mixing tube elements 230 of a fuel nozzle 22 according to embodiments of the present disclosure.

[0038] As shown, the mixing tube element 300 includes a body 302 extending between a first (forward) end 304 and a second (aft) end 306. A passageway 308 is defined within the body 302 and extends through the body 302 between the first end 304 and the second end 306. With reference to FIGS. 4, 5, and 7, the first end 304 is closed, preventing fluid from flowing therethrough. With reference to FIGS. 4, 5, and 6, the second end 306 is open, allowing fluid to exit the passageway 308 through the second end 306. In this manner, the second end 306 may function as an outlet for the passageway 308. As described herein, a premixed flow of the first fluid 240 and the second fluid 250 may be discharged from the passageway 308 through the second end 306.

[0039] In an exemplary embodiment, body 302 is cylindrical. Alternatively, body 302 may have a conical, cubical, or other suitable shape. Further, in an exemplary embodiment, passageway 308 is cylindrical. Alternatively, passageway 308 may have a conical, cubical, or other suitable shape.

[0040] The passageway 308 may have a length 310 (e.g., a maximum length) defined between the first end 304 and the second end 306. The passageway 308 may also have a width 312 (e.g., a maximum width), which may be a diameter if the body 302 is cylindrical.

[0041] As shown, one or more first fluid inlets 320 are defined in body 302 (in some embodiments, proximate first end 304). First fluid inlets 320 are in fluid communication with first fluid plenum 212 and passageway 308, such that fluid passing through first fluid inlet 320 flows into passageway 308. In an exemplary embodiment, first fluid 240 flows from first fluid plenum 212 through first fluid inlet 320 and into passageway 308.

[0042] In the exemplary embodiment, a plurality of first fluid inlets 320 are defined in the body 302. Additionally, in one exemplary embodiment, four first fluid inlets 320 are defined in the body 302. The first fluid inlets 320 may be spaced approximately equally (equally spaced in the exemplary embodiment) around the circumference of the body 302 in the illustrated exemplary embodiment. Thus, each first fluid inlet 320 is approximately equally (equally spaced in the exemplary embodiment) positioned from an adjacent first fluid inlet 320 around the circumference of the body 302.

[0043] First fluid inlet 320 may be defined in body 302 along length 310 between first end 304 and second end 306 (e.g., proximate first end 304 and distal from second end 306 along length 310). Further, in an exemplary embodiment, multiple first fluid inlets 320 may be approximately equally spaced (equally spaced in an exemplary embodiment) from first end 304 along length 310.

[0044] The arrangement and spacing of the first fluid inlets 320 in the body 302 is particularly advantageous because as the first fluid 240 flows through each of the first fluid inlets 320, it may impinge on the first fluid 240 flowing through other first fluid inlets 320 (e.g., the opposite first fluid inlets 320). For example, such impingement may create a strong turbulence field, promoting improved mixing with the second fluid 250 and improving premixing within the mixing tube element 300.

[0045] In the exemplary embodiment, the first fluid inlet 320 has an elongated shape (e.g., an elongated slot shape having a length (axial) greater than a width (circumferential) as shown). Such an elongated slot includes straight sides and curved ends as shown. Such an elongated slot has a major axis extending axially. Alternatively, other suitable shapes (e.g., other suitable elongated shapes) may be utilized.

[0046] As shown, one or more second fluid inlets 330 are defined in body 302 (in some embodiments, proximate first end 304). Second fluid inlets 330 are in fluid communication with passageways 308, such that fluid passing through second fluid inlets 330 flows into passageways 308. In an exemplary embodiment, second fluid 250 flows from second fluid plenum 222 through second fluid inlets 330 into passageways 308.

[0047] In the exemplary embodiment, a plurality of second fluid inlets 330 are defined as fluid injection ports in the body 302. In the exemplary embodiment shown, the second fluid inlets 330 may be spaced approximately equally (equally spaced in the exemplary embodiment) around the circumference of the body 302. Thus, each second fluid inlet 330 is positioned approximately equally (equally spaced in the exemplary embodiment) from an adjacent second fluid inlet 330 around the circumference of the body 302.

[0048] Second fluid inlet 330 may be defined in body 302 along length 310 between first end 304 and second end 306 (e.g., proximate first end 304 and distal from second end 306 along length 310). In an exemplary embodiment, second fluid inlet 330 may be positioned along length 310 between first fluid inlet 320 and second end 306. Further, in an exemplary embodiment, multiple second fluid inlets 330 may be positioned approximately equally spaced (equally spaced in an exemplary embodiment) from first end 304 along length 310.

[0049] As described above, the passageway 308 can have a length 310 and a width (inner diameter) 312. In an exemplary embodiment, the length 310 can be approximately two times or less the width 312. Such dimensions are particularly preferred due to various other design features described herein, such as the placement and spacing of the first fluid inlets 320 and the closed first end 304. In particular, the ratio of the length 310 to the width 312 is significantly shorter than that of known mixing tube element designs, which may have a length-to-width ratio of 8:1. This smaller ratio, combined with the improved premixing described herein, advantageously reduces the risk of flame retention in the element 300 and the nozzle 22 as a whole. Furthermore, the smaller ratio contributes to faster build times for the nozzle 22 when fabricated by additive manufacturing, as described below.

[0050] In some embodiments, the fuel nozzle 22 or portions thereof (including the mixing tube element 300, the housing 210, the forward plate 231, and the end plate 232 that define the first fluid plenum 212 and the second fluid plenum 222) can be formed in an additive manufacturing system, and in some embodiments, can be formed as a single, integral part. An exemplary additive manufacturing system is described below with reference to FIG. 8.

[0051] To illustrate one example of an additive manufacturing system and process, a schematic / block diagram of an additive manufacturing system 1000 for making an object 1220 (which may be a fuel nozzle 22 or a portion thereof, as described herein) is shown in Figure 8. The additive manufacturing system 1000 may be configured for direct metal laser sintering (DMLS) or direct metal laser melting (DMLM). For example, the additive manufacturing system 1000 may produce an object such as a fuel nozzle 22 or a portion thereof, as described herein.

[0052] For example, object 1220 may be fabricated layer-by-layer by sintering or melting powder material in powder bed 1120 using an energy beam 1360 generated by a source such as laser 1200. The powder to be melted by the energy beam is supplied by reservoir 1260 and spread evenly on build plate 1020 using recoater arm 1160, which moves in recoater direction 1340 to maintain the powder at level 1180 and removes excess powder material above powder level 1180 into waste container 1280. The energy beam 1360 sinters or melts a cross-sectional layer of the object to be built under the control of galvanometer scanner 1320. The build plate 1020 is lowered, and another layer of powder is spread on the build plate and the object to be built, followed by sequential melting / sintering of the powder by laser 1200. This process is repeated until object 1220 is fully built from the fused / sintered powder material.

[0053] The laser 1200 (e.g., energy beam 1360) may be controlled by a computer system including a processor and a memory. The computer system may determine a scan pattern for each layer and control the laser 1200 to irradiate the powder material according to the scan pattern. After the fabrication of the object 1220 is complete, the object 1220 may be subjected to various post-processing steps. Post-processing steps include removing excess powder, such as by blowing or vacuum suction. Other post-processing steps include stress relief processes. Additionally, thermal and chemical post-processing methods may be used to finish the object 1220.

[0054] In an exemplary embodiment, the additive manufacturing system 1000 may define a cylindrical coordinate system having an axial build direction AAM (or build direction), a radial direction RAM perpendicular to the build direction, and a circumferential direction CAM extending around the build direction.

[0055] As noted above, exemplary embodiments of the present technology involve the use of additive manufacturing machines or methods. As used herein, the terms "additive manufacturing" or "additive manufacturing techniques or processes" generally refer to: A manufacturing process in which one or more layers of material are sequentially deposited to "build up" a three-dimensional part, layer by layer. Successive layers usually fuse together to form a monolithic part, which may have various integral subcomponents.

[0056] The additive manufacturing processes described herein may be used to form parts using any suitable material. For example, the material may be a metal, ceramic, or other suitable material, and may be in a solid, liquid, powder, sheet material, wire, or other suitable form. More specifically, in exemplary embodiments of the present technology, the additively manufactured parts described herein may be formed partially or entirely from materials including, but not limited to, pure metals, nickel alloys, chromium alloys, titanium alloys, magnesium, magnesium alloys, aluminum, aluminum alloys, iron, iron alloys, stainless steel, and nickel- or cobalt-based superalloys (e.g., those available from Special Metals under the trade name Inconel®), or some combination of these materials. These materials are examples of materials suitable for use in the additive manufacturing processes described herein, and may be collectively referred to as "additive manufacturing materials."

[0057] As used herein, "fusing" refers to a process suitable for creating a bonded layer of any of the materials described above. For example, if the material is a ceramic, the bond may be created by a sintering process. If the material is a powder metal, the bond may be created by a melting or sintering process. As will be apparent to those skilled in the art, other methods of fusing materials to produce parts by additive manufacturing are possible and may be used in conjunction with the disclosed techniques.

[0058] Each successive layer may be, for example, about 10 μm to 200 μm, although the thickness may be selected based on any number of parameters and may be any suitable dimension in other embodiments. Thus, utilizing the additive manufacturing methods described above, parts described herein may have a cross-section as thin as the thickness (e.g., 10 μm) of one of the associated powder layers utilized in the additive manufacturing process.

[0059] It should be noted that, in exemplary embodiments, some features of the parts described herein were not previously possible due to manufacturing constraints. However, the inventors have advantageously taken advantage of advances in additive manufacturing technology to develop exemplary embodiments of parts according to the presently disclosed technology. While the present disclosure is not limited to the use of additive manufacturing to form these parts generally, additive manufacturing offers various manufacturing advantages, including ease of manufacture, reduced cost, and improved accuracy.

[0060] The details of the disclosed technology are illustrated by the following exemplary embodiments. [Embodiment Item 1] In a first embodiment, a fuel nozzle 22 for a combustor 10 of a turbomachine is disclosed, including a housing 210 and a plurality of mixing tube elements 230 or 300 enclosed by the housing 210. At least one of the plurality of mixing tube elements includes a body 302 extending between a first end 304 and a second end 306, the body 302 defining a passageway 308 therethrough between the first end 304 and the second end 306, the first end being closed and the second end being open. The body 302 further defines a first fluid inlet 320 and a second fluid inlet 330. The first fluid inlet is defined between the first end and the second end. The second fluid inlet is defined between the first fluid inlet and the second end. [Embodiment 2] In a second aspect, a turbomachine 100 is disclosed that includes a compressor section 114, a combustion section including a combustor 10, and a turbine section 118. The combustor includes an end cover 26 and a fuel nozzle 22. The fuel nozzle 22 is the fuel nozzle described above. Specifically, the fuel nozzle includes a plurality of mixing tube elements 230 or 300 enclosed by a housing 210. One or more of the plurality of mixing tube elements includes a body 302 extending between a first end 304 and a second end 306, defining a passageway 308 therethrough between the first end 304 and the second end 306. The first end 304 is closed, and the second end 306 is open. The body further defines a first fluid inlet 320 and a second fluid inlet 330. The first fluid inlet 320 is defined between the first end 304 and the second end 306. A second fluid inlet 330 is defined between the first fluid inlet 320 and the second end 306 . [Embodiment 3] In a particular embodiment of the turbomachine 100 or fuel nozzle 22 described above, the fuel nozzle 22 includes a forward plate 231 and an aft plate 232 axially spaced from the forward plate 231, with the forward plate 231 and the housing 210 defining a first fluid plenum 212 upstream of the forward plate 231, and the forward plate 231, the housing 210, and the aft plate 232 collectively defining a second fluid plenum 222 between the forward plate 231 and the aft plate 232. [Embodiment 4] In a more specific embodiment of the turbomachine 100 or fuel nozzle 22 described above, the first fluid inlet 320 is an elongated slot having an axially oriented major axis, and the first fluid inlet 320 is in fluid communication with the first fluid plenum 212. [Embodiment 5] In the exemplary embodiment of the turbomachine 100 or fuel nozzle 22 described above, the first fluid inlet 320 is a plurality of first fluid inlets 320 in fluid communication with the first fluid plenum 212 . [Embodiment 6] The plurality of first fluid inlets 320 may be approximately equally spaced around the circumference of the body 302 . [Embodiment 7] The plurality of first fluid inlets 320 may be four first fluid inlets. [Embodiment 8] In the embodiments of the turbomachine 100 or fuel nozzle 22 described above, the second fluid inlet 330 may be in fluid communication with the second fluid plenum 222 . [Embodiment Item 9] In the turbomachine 100 or fuel nozzle 22 described above, the passage 308 may define a maximum length 310 and a maximum width 312 from the first end 304 to the second end 306, where the maximum length 310 is less than or equal to approximately two times the maximum width 312. [Embodiment Item 10] Alternatively, the passageway 308 defines a maximum length from the first end 304 to the second end 306 and a maximum width 312 , with the maximum length 310 being equal to approximately two times the maximum width 312 . [Embodiment Item 11] In the exemplary embodiment of the turbomachine 100 or fuel nozzle 22 described above, at least one of the plurality of mixing tube elements 230, 300 is a plurality of mixing tube elements.

[0061] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using the devices and systems and practicing the methods. [Explanation of symbols]

[0062] 10 Combustor 12 Liner 14 Outer sleeve 20 Headend 22 fuel nozzle 24 Fuel inlet 26 End cover 28 Combustor Cap 32 Annulus 50 Primary combustion zone 60 Secondary combustion zone 100 Gas Turbine Engine 112 Intake section 114 Compressor Section 116 Combustion Section 118 Turbine Section 120 Exhaust Section 122 Shaft 134 Combustion Gas 200 Fluid supply conduit 202 Entrance 204 Exit 206 Fluid passage 210 outer housing 212 first fluid plenum 222 Second fluid plenum 230 Mixing tube element 231 Front Plate 232 End Plate 300 Mixing tube element 302 Main Unit 304 first end 306 Second End 308 Passage 320 first fluid inlet 330 second fluid inlet ?

Claims

1. 1. A fuel nozzle for a combustor of a turbomachine, the fuel nozzle comprising: a housing; and a plurality of mixing tube elements enclosed in the housing, wherein one or more of the plurality of mixing tube elements includes a body extending between a first end and a second end, the first end being closed and the second end being open, the body further defining a first fluid inlet and a second fluid inlet, the first fluid inlet being defined between the first end and the second end, and the second fluid inlet being defined between the first fluid inlet and the second end.

2. 2. The fuel nozzle of claim 1, wherein the fuel nozzle comprises a forward plate and an aft plate axially spaced from the forward plate, the forward plate and the housing defining a first fluid plenum upstream of the forward plate, and the forward plate, the housing, and the aft plate collectively defining a second fluid plenum between the forward plate and the aft plate.

3. 3. The fuel nozzle of claim 2, wherein the first fluid inlet is an elongated slot having an axially oriented major axis, the first fluid inlet in fluid communication with the first fluid plenum.

4. The fuel nozzle of claim 2 or claim 3, wherein the plurality of first fluid inlets (320) are in fluid communication with the first fluid plenum (212).

5. The fuel nozzle of claim 4 , wherein one or more of the plurality of first fluid inlets is an elongated slot having an axially oriented major axis.

6. The fuel nozzle of claim 5 , wherein each first fluid inlet of the plurality of first fluid inlets is an elongated slot having an axially oriented major axis.

7. The fuel nozzle of claim 4 , wherein the plurality of first fluid inlets are at least approximately equally spaced around a circumference of the body.

8. The fuel nozzle of claim 4 , wherein the plurality of first fluid inlets is four first fluid inlets.

9. The fuel nozzle of any one of claims 2 to 8, wherein the second fluid inlet (330) is in fluid communication with the second fluid plenum (222).

10. 10. The fuel nozzle of claim 1, wherein the passage defines a maximum length from a first end to a second end and a maximum width, the maximum length being less than or equal to about two times the maximum width.

11. The fuel nozzle of claim 10 , wherein the maximum length (310) is at least approximately equal to twice the maximum width (312).

12. 10. The fuel nozzle of claim 1, wherein each mixing tube element of the plurality of mixing tube elements includes a body extending between a first end and a second end defining a passageway therethrough, the first end being closed and the second end being open, the body further defining a first fluid inlet and a second fluid inlet, the first fluid inlet being defined between the first end and the second end and the second fluid inlet being defined between the first fluid inlet and the second end.

13. 13. A turbomachine comprising: a compressor section (114), a combustion section (116), and a turbine section (118), the combustion section comprising a combustor (10), the combustor comprising an end cover (26) and a fuel nozzle (22), the fuel nozzle being the fuel nozzle of any one of claims 1 to 12.

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